The gyoji also carries a knife so that he can disembowel himself if he gets a call wrong. Obviously they don't actually do this, but that's the mentality they have.
The rank of a gyoji can be determined by the color of the tassel of his fan: purple or purple and white for the tate-gyoji, red for those correpsonding to san yaku, red and white for maku-uchi, blue and white for juryo, and blue or black for the ranks below.
The higher ranked referees wear tabi (Japanese split-toe socks) and zori (straw sandals). In contrast, the lower ranks are barefooted.
The gyoji enters the dohyo with the wrestlers and calls out the names of each in a specially trained voice. When it is time for the combatants to begin, the gyoji gives the signal with his fan, and in the course of the match keeps a watchful eye on the wrestler's movements and shouts words of encouragement.
Around the four sides of the dohyo sit judges wearing black formal wear. Should there be any doubt about the referee's decision, the judges climb into the ring and settle the matter amongst themselves. The can over-rule the referee's decision, and they can order a rematch. There are five judges for all matches.
After entering the dohyo, each rikishi goes through a series of symbolic movements (the raising of the arms to the side as well as the stamping of feet). To cleanse his mind and body, he symbolically rinses his mouth with water, the source of purity, and wipes his body with a paper towel.
Each rikishi also scatters a handful of salt to purify the ring. This is supposed to keep him safe from injuries. Only the maku-ichi, juryo, and maku-shita rikishi can throw salt.
The rikishi then squat and face each other in the center of the ring, crouch forward in a "get set" position supporting themselves with their fists on the ground. This portion of the ritual is called the shikiri.
They do not begin the match at once. They engage in a kind of psychological "cold warfare". They go back to their corners for more salt, scatter it, and return to glare at each other. Or they may return to their corners to wipe their faces and take more drinks of water. They repeat the process again and again usually for the full four minutes allowed by the rules.
This ritual gives the rikishi time to work themselves and the spectators up for an exciting match.
When both wrestlers place their hands on the ground, the match begins!
Ozumo - The sport of sumo
Rikishi - A sumo wrestler
Dohyo - The sumo ring
Mawashi - The belt that rikishi wear.
Honbasho or Basho - The six tournaments held throughout the year. Honbasho is technically correct, but everyone uses basho
Kachi-koshi - A winning tournament. When a rikishi has a tournament with more wins than losses (at least 8-7) he has a kachi-koshi
Make-koshi - A losing tournament. When a rikishi has more losses than wins (at least 7-8 ).
Yusho - The championship for a basho. Whoever in the top division has more wins than everyone else gets the yusho. (In the event of a tie on the final day the two tied rikishi have a match against each other referred to as a "playoff" which doesn't count towards their records).
Zensho yusho - A flawless tournament. When a rikishi has all wins and no losses and wins the yusho it's called a zensho yusho.
Heya - A sumo stable. Where many of the rikishi train, eat, sleep, and live. When referring to a specific heya, you would say Miyagino beya with a "b"
Gyoji - Referee for a sumo match
This video shows the good and bad of sumo, illustrating how difficult it is for the younger wrestlers, and how rigid their training and lives are.